Embodiments of the present invention relate to a near field transaction method and a near field transaction system.
The last few years, the apparition of inductive coupling contactless communication techniques, also called NFC (Near Field Communication) techniques, changed the field of chip cards, making it possible first to make contactless payment cards, and then, to integrate a secure processor and a NFC controller into electronic portable objects such as mobile phones, to perform near field transactions using them.
FIG. 1 schematically shows a conventional transaction system including a contactless chip card CC1 and a transaction terminal TT. The terminal TT is, for example, a cash point, a sales outlet (e.g., ticket machine, food and drink dispenser, or the like) an automatic paying access control terminal (e.g., metro access terminal, bus payment terminal, or the like).
The contactless card CC1 includes a Contactless Integrated Circuit CIC provided with a secure processor and an antenna coil AC1 connected to the integrated circuit. The terminal TT includes an antenna coil AC2 and is configured to perform a near field transaction with the card CC1 by emitting a magnetic field FLD. The transaction includes exchanging Application Protocol Data Units APDU which will be hereinafter referred to as “application data” for the sake of simplicity. The application data APDU include commands CAPDU sent by the terminal and answers RAPDU sent by the card. The terminal TT may be linked in real time or delay time to a transaction server SV0, to validate a payment and/or debit an account of the user.
FIG. 2 schematically shows a transaction system including a mobile phone HD1 and the transaction terminal TT. The phone HD1 includes a main processor PROC1, a radiocommunication circuit RCCT, a secure processor PROC2 of SIM card (Subscriber Identity Module), a NFC controller referenced “NFCC,” an antenna coil AC3 linked to the controller NFCC and a secure processor PROC3 configured to perform NFC transactions.
The processor PROC3 includes a central processing unit CPU, an operating system OS, a Card Application Program CAP and/or a Reader Application Program RAP. The processor PROC3 is linked to the controller NFCC through a bus BS1, for example a Single Wire Protocol bus SWP. In practice, the processor PROC3 may be a Universal Integrated Circuit Card UICC, for example of the mini-SIM or micro-SIM type.
An example of functional architecture of the controller NFCC and the processor PROC3 is shown in FIG. 3. The controller NFCC includes a host controller HC and a Contactless Front End Interface CLF which is linked to the antenna coil AC3. In practice, the host controller HC and the interface CLF may be integrated into the same semiconductor chip, such as the MicroRead® chip commercialized by the applicant.
The bus BS1 linking the processor PROC3 and the controller NFCC is used as physical support for a communication interface called Host Controller Interface (HCI) through which the controller NFCC and the processor PROC3 exchange data in accordance with a Host Controller Protocol HCP. The interface HCI and the protocol HCP are described in the specifications ETSI TS 102 622 of the European Telecommunications Standards Institute, called “Smart Cards; Universal Integrated Circuit Card (UICC); Contactless Front-end (CLF) interface; Host Controller Interface (HCI).” The protocol HCP provides the routing of data according to routing channels called “pipes,” through which application data APDU are exchanged during a transaction between the processor PROC3 and the transaction terminal TT.
The interface CLF may generally operate according to several RF technologies referred to as “RFTi” in FIG. 3, for example “Type A” or “Type B,” such as defined by ISO/IEC 14443 parts 2, 3 and 4, “Type B′” such as defined by ISO/IEC 14443-2, with a standard framing such as defined by ISO/IEC 14443-3, and “Type F” such as defined by ISO 18092 (as passive mode at 212 and 424 kilobytes per second) or by the Japanese industrial standard JIS X 6319-4.
During the execution of the card application CAP, the processor PROC3 emulates a contactless card and uses the controller NFCC in passive mode to perform a transaction with a transaction terminal TT which emits the magnetic field FLD. A pipe P1 is first opened between the card application CAP and the interface CLF of the controller NFCC, which is configured for the occasion in an RFTi technology. The terminal TT sends to the controller NFCC commands CAPDU that the controller transmits to the processor PROC3 through the pipe P1. The processor PROC3 emits answers RAPDU which are transmitted to the controller NFCC through the pipe P1, and then transmitted to the terminal TT by the controller NFCC, through a pipe RF.
During the execution of the reader application RAP, the processor PROC3 performs a transaction with a contactless integrated circuit CIC arranged in a contactless card CC1 or another support. The controller NFCC is in an active operating mode where it emits a magnetic field FLD. A pipe P1 is first opened between the reader application RAP and the interface CLF of the controller NFCC, which is configured for the occasion in an RFTi technology. The reader application RAP then emits commands CAPDU which are transmitted to the controller NFCC through the pipe P2, and then transmitted to the integrated circuit CIC through a pipe RF. The contactless integrated circuit CIC sends to the controller NFCC answers RAPDU that the controller transmits to the processor PROC3 through the pipe P2.
It is known that the development of the NFC technology is closely related to the development of card applications in portable devices such as mobile phones, so as to use such portable devices as contactless chip cards. Although infrastructures provided with NFC transaction terminals already exist, in particular in the field of payment, the integration of secure processors into mobile phones to execute such applications is not carried out at a sufficient rate to allow the NFC technology to be developed as expected.
A constraint which slows down the development is the complexity and cost of a secure processor such as the processor PROC3 shown in FIGS. 2 and 3. It must preferably be able to execute various card applications and must therefore contain as many bank keys (encryption keys) as card applications supplied by different banks. It must in addition have a sufficient computing power to carry out complex encryption calculations during the authentication phase of a transaction. In addition, the personalization of the processor, i.e., loading a card application CAP into the memory thereof, is a complex operation which must be highly secured and requires external managers such as a Trusted Service Manager TSM. Finally, in the event of phone theft or during a maintenance operation of the phone, the processor PROC3 is susceptible of being attacked by a fraud so as to discover the bank keys it includes.
It may therefore be wished to provide a method allowing a NFC transaction to be performed via a portable device of the mobile phone type having an architecture which is simpler and less expensive to implement than known architectures.